In an electric storage element built in an electric storage cell, heat is generated along with charge/discharge operation. This heat is transferred through various paths around the electric storage cell, finally, to an air-cooled or liquid-cooled medium.
As a technique of radiating the heat in the electric storage cell to the outside, JP2003-282375A discloses an electric double layer capacitor housed in an exothermal hard casing using a heat-conductive chassis that interposes a heat radiation fin of a soft casing.
In addition, in JP2005-51074A, a fin is provided in a terminal protruding to the outside of the electric double layer capacitor.